@misc{cryptoeprint:2010:651,
author = {Rishiraj Bhattacharyya and Avradip Mandal},
title = {On the Impossibility of Instantiating PSS in the Standard Model },
howpublished = {Cryptology ePrint Archive, Report 2010/651},
year = {2010},
note = {\url{http://eprint.iacr.org/}},
}
You will need the url.sty package (comes with most LaTeX installations) for the last line. Otherwise, remove the \url command.